When light passes from one medium to another, the speed at which the light travels will change depending on the parameters of the materials. This principle can be seen when looking at a straw in a glass or an oarsman on the river, where the straw or oar appears to be bent at the water/air interface.
The ratio or change in the speed of light is called refractive index and instruments that measure this are called refractometers.
The refractive index of a liquid is related to its concentration and so a refractometer can display the concentration in suitable units, such as °Brix (sucrose), total dissolved solids (TDS), Baume, probable alcohol, sodium chloride, urea and urine specific gravity to name just a few.
Refractometers are simple optical instruments used throughout industry for over 150 years and have now developed in to sophisticated digital instruments capable of measuring the % of dissolved solids to 3 decimal places.
Bellingham + Stanley designed OPTi digital handheld refractometers are manufactured in the UK as highly reliable premium quality instruments suitable for use in the harshest of environments across a wide application scope. Buy today from our online store.
Handheld refractometers are low-cost, portable instruments used for ‘on the spot’ determination of Refractive Index (RI) of liquids or the concentration of solutions. Offering a choice of scales, Eclipse refractometers can be used in a multitude of applications across many and varied industries.
The all new RFM300-M series refractometers are the ultimate instruments for installation in demanding factory environments as well as for use as a primary quality control tool.
The RFM300 now boasts a 7" touchscreen user interface with easy to use menus giving this powerful refractometer, suitable for harsh factory environments, a fresh modern look and feel.
The RFM900-T Series of Peltier temperature controlled refractometers combine latest opto-electronic principles with durability and ease of use via a touchscreen user interface. Offering a wide refractive index range and high precision measurement to six decimals RI, the RFM970-T version is ideal for use in pharmaceutical applications operating in accordance with Pharmacopeia and FDA regulation 21 CFR Part 11; as well as in petrochemical, chemical, and aroma applications.
For many years, beverage manufacturers have adopted digital refractometers as their primary instrument for measuring the final dilution ratio (°Brix) of re-constituted fruit juice not only to assure product quality but also in an attempt to reduce losses by tightly controlling concentrate yields. However, due to the nature of the sample, common refractometers show a variation in the reading caused by sample settling. The Pro-Juice refractometer conditions the sample prior to measurement allowing for extremely precise analysis to be made allowing for higher yields from concetrates that translates directly to increased profits for orange juice packers.
The Abbe 5 is an affordable refractometer ideally suited for use where a wide refractive index measurement range is required such as in small contract laboratories or applications where sample throughput is relatively low. The instrument is also ideal for practical demonstrations and experiments in chemistry and physics laboratories of schools, colleges and universities and is the perfect partner to the new Model D7 optical polarimeter.
Abbe refractometers date back to the birth of opto-mechanical instrumentation when Ernst Abbe created an instrument to categorise the behaviour of glass that was to be used in the first microscopes created with his then partners Otto Schott and Carl Zeiss.
Today Abbe refractometers are still used in "purist applications" especially where measurements are required at wavelengths other than sodium or where solids are to be assessed such as measuring the dispersion of glass, polymers and even hydrocarbons. They are also used to measure liquid anasthetic.